From: Joeseph Chang <joech...@codeaurora.org>

msg_written_handler() may set ssif_info->multi_data to NULL
when using ipmitool to write fru.
Change the ssif i2c send data sequence in msg_written_handler()
to fix NULL pointer kernel panic and incorrect ssif_info->multi_pos.

Signed-off-by: Joeseph Chang <joech...@codeaurora.org>
---
 drivers/char/ipmi/ipmi_ssif.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
index cca6e5b..39346ee 100644
--- a/drivers/char/ipmi/ipmi_ssif.c
+++ b/drivers/char/ipmi/ipmi_ssif.c
@@ -899,21 +899,13 @@ static void msg_written_handler(struct ssif_info 
*ssif_info, int result,
                        left = 32;
                /* Length byte. */
                ssif_info->multi_data[ssif_info->multi_pos] = left;
-               ssif_info->multi_pos += left;
-               if (left < 32)
-                       /*
-                        * Write is finished.  Note that we must end
-                        * with a write of less than 32 bytes to
-                        * complete the transaction, even if it is
-                        * zero bytes.
-                        */
-                       ssif_info->multi_data = NULL;
 
                rv = ssif_i2c_send(ssif_info, msg_written_handler,
                                  I2C_SMBUS_WRITE,
                                  SSIF_IPMI_MULTI_PART_REQUEST_MIDDLE,
                                  ssif_info->multi_data + ssif_info->multi_pos,
                                  I2C_SMBUS_BLOCK_DATA);
+
                if (rv < 0) {
                        /* request failed, just return the error. */
                        ssif_inc_stat(ssif_info, send_errors);
@@ -922,6 +914,16 @@ static void msg_written_handler(struct ssif_info 
*ssif_info, int result,
                                pr_info("Error from i2c_non_blocking_op(3)\n");
                        msg_done_handler(ssif_info, -EIO, NULL, 0);
                }
+
+               ssif_info->multi_pos += left;
+               if (left < 32)
+                       /*
+                        * Write is finished.  Note that we must end
+                        * with a write of less than 32 bytes to
+                        * complete the transaction, even if it is
+                        * zero bytes.
+                        */
+                       ssif_info->multi_data = NULL;
        } else {
                /* Ready to request the result. */
                unsigned long oflags, *flags;
-- 
1.9.1

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